Centerless grinding machinery



Ju 14, @310 CIIBQQTH 31,814,362

CENTERLESS GRINDING MACHINERY Filed April 9. 1928 2 Sheets-Sheet 1 CLEMENTBMTH.

July 14, 1931. c. BOOTH 1,814,362

CENTERLES-S GRINDING MACHINERY Filed April 9. 1928 2 Sheets-Sheet 2 53 as as 4 as 2, 19

30 [an 48 28 EHHE r 47 VIII/111107111113 7 .50 1 /z9 EVA 27 CL EMENT 800m I v 3 5 r K r! Patented July 14, 1931 UNITED STATES PATENT OFFICE CLEMENT BOOTH, OF CINCINNATI, OHIO, ASSIGNOR T'O CINCINNATI GRINDERS IN- CORPORATED, F CINCINNATI, OHIO, A CORPORATION OF OHIO CENTERLESS GRINDING MACHINERY Application filed April 9, 1928 Serial No. 268,543.

This invention relates to improvements in centrically located tapered shanks on twist drills or like members. I

One'of the principal ob ect s of the. present invention is the provision of improved means forv properly positioning and guiding the tapered shank porton of a twist drill or like member during the accurate forma tion of the taper thereon.

A further object of the invention is the provision of a combination of improved -mechanisms for joint engagement with a floating work piece to insure the proper concentric production of a second surface thereon as respects a previously formed portion thereof.

A further ob ect of the lnvention 1s the provision of an improved work holding fixture which will facilitate the introduction of work in the grinding throat of a centerless grinder and the subsequent withdrawal thereof at the completion of the grinding operation.

An additional object of the invention is the provision of an attachment for application to a standard centerless grinder which will facilitate theproduction of articles therein by the infeed method.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification taken in conjunction with theaccompanying drawings forming a part thereof, and

it will beunderstood that I may make any modifications in the specific structural dc:

4o tails hereinafter disclosed within the-scope tion of the fixture and associate portions of the machine.

Figure 5 is a transverse section as on line 55 of Figure 4:. I

Figure 6 is a section on line 66 of F igure 3 and Figure 7 is a section through the Figure 3.

In the drawings the numeral 10 designates the bed of a conventional centerless grinder .double gimbal bearing as on line 7-7 of having the housing 11 for the grinding l wheel 12 which is operated ata high or grinding rate of speed in the direction indicated by the arrow on the. housing in Fig-- ure 1.

Mounted on the bed 10 is a slide 13 having movable therewith and thereon relative thereto the regulating wheel unit 14 supporting ,the regulatinggwvheel 15. This wheel is located in oppo tion to the grinding Wheel and has its inner operative surface moving in the opposite direction from that of the grinding wheel as is also indicated by the arrow. An'adjusting screw 16 and pilot wheel 17 inter-engaged with bracket 18 on bed 10 serve to move the slide rest blade 19 having an angularly disposed upper surface 20 incliningupwardly in the direction of and in opposition to the direction of movement of the grinding wheel. By reference particularly to Figures 3 and 4 of the drawings it will be noted that the work rest blade-i-nplace of being continuous in form is provided with the upstanding lug 21 forengagement with the periphery of the shank 22 of-drill barrel 23 which shank is intended-to be formed by the present machineto proper accurate diameter and concentriowith the previously ground barrel portion thereof. 5

It is further to be noted that this shank portion 22 is of tapered form to fit the usual tapered chuck or holder and that consequently the throat opening between opposed operative faces of the grinding and regulating wheels is of tapered formation.

It is to be understood that the taper may be equally formed on the faces of the grinding and regulating wheels as has been illustrated or one of these may be disposed parallel with its axis and a double taper formed on the other. In either event, however, the regulating wheel in place of having continuous contact with the work piece is preferably shaped or formed as by the truing device 24 with a projecting. circumferential rib 25 corresponding in location to the lug 21 on the work rest blade and designed to cooperate with said lug and with a predetermined portion of the work piece for the final accurate supporting and positioning of the work piece with respect to the grinding wheel.

To cooperate with the parts just described the work rest blade or bracket 180 preferably carries an abutment or stop 26 to limit endwise or axial movement of the work piece into the machine.

The bracket 180 has a forwardly projecting portion 27 which serves as a'support for the work holding and controlling fixture. This fixture comprises a bracket member adjustably secured to the portion 27 by T bolts 29 and having an upstanding portion 28 in turn adjustably supporting the block 30. Block 30 inwardly terminates in yoke arms 31 hearing pivot screws 32 engaging ring 33 which in turn has pivot screws 34 'at right angles to screws 32 for engagement with the work uiding sleeve 35. It will thus be noted t at. sleeve 35 is supported by a universal joint or double gimbal bearing permitting of same being swung from a raised loading position as-shown in Figure 4 to the operative position of Figure 3 and return and alsopermitting of lateral play or swinging movement of the sleeve as limited by stop plate 36 adjustably secured 'to lug 37 and located at the regulating wheel side of the machine as most clearly illustrated in Figure 2. Sleeve 35 has a central bore 38 of size to just receive the larger or point end of the drill barrel so that this portion 23 of the work may be readily slipped into the sleeve when in raised position as limited by the rib 39.

Rib 39 surrounds aperture 40 designed to receive plunger 41 having a portion 42 sliding in ore 43 of block 30. This sliding movement is controlled by pin 44 riding in slot 45' and engaged in vertical slot 46 of slide block 47 which moves in the guide slot 48 of bracket 28. An actuating handle 49 is suitably pivoted as to bracket'27 and has a pin 50 engaged in block 47 for actuation thereof.

;Since the fixture in question is intended for accurate positioning of the work pieces to insure proper concentric grinding thereof it is' desirable that it be capable of .de-

,sired vertical adjustment. To this end block without in any wise disturbing the operative connection between said parts.

In the operation the sleeve 35 is swung into an upward position as shown in Figure 4 and a work piece inserted till it rests on rib 39. The sleeve is then swung downward to introduce theshank 22 thereof in the throat between grinding and regulating wheels as shown in Figure 3. As it is swung downward. it is pressed against stop plate 36 bringing the fixture toward the regulating wheel and on account of the retracted position of the work there will be no engagement between work and grinding wheel during this position. In work of the type here in question the barrel of the drill is preferably formed with a cut back or relieving angle which is to say that it tapers gradually from the point toward the tapered shank but at a less degree of taper than said shank. Stop 36 is so located that at the completion of the grinding the longitudinally tapered barrel will'have line contact with the work supporting sleeve at the regulating wheel side producin a clearance between guide sleeve and wor as indicated at 54'. Since the regulating wheel does not wear away during grinding of an individual work piece and since the sleeve 1s also nonwearing the two together form an absolute sure absolute concentricity of the barrel and tapered shank portions of the work piece.

In. the performance of-the grinding operation after the sleeve bearing the work has been swung into proper position handle 49 is swung inwardly projecting pusher 41 through aperture 40 into engagement with the point of the drill. This action shifts the work axially into the grinding throat between grinding and regulating wheels, the tapered shank riding along rib 21 on the work rest and guided by the work controlling rib on the regulating wheel is ground off by the action of the rinding wheel and as ground tends to rece e toward the regu v lating wheel the fixture swinging about pivots 34 until it comes to rest against stop 36 but still being free for ve'rticall movement to compensate for any additional rise of the work in its movement along the work rest until limited by engagement with stop 26. It will be apparent that due to the double gimbal bearing support for the fixture the same is free to follow the movement of the work in all directions except as limited by stop 36 while on account of the employment of ribs or projections 21 and 25 on the work rest and regulating wheel respectively the tapered shank being ground is also capable of limited movement to absolutely find and position itself and insure proper concentric grinding with a predetermined portion of said tapered shank employed as a determinant; This is of particular value in the event ofslightly warped shanks or the like since the central position on the shank employed facilitates proper supporting of the shank during the grinding off of the terminal portions thereof in curing the warped, bent or out of round conditions thereof.

I claim:

1. A machine for the centerless production of concentric'work piece surfaces comprising opposed grinding and regulating wheels forming a work receiving throat. therebetween, a work rest projecting within the throat for supporting work pieces therein and a work supporting fixture mounted ad,- jacent said throat and including a work holding member for engaging a terminal portion of the work and oscillatable from a work receiving position to a position topresent a projecting portion of the work on the work rest in the throat between grinding and regulating wheels, and means supporting the fixture for free floating movement to permit the work to automatically adjust itself to the grinding throat.

2. A machine for the centerless production of concentric work piece surfaces comprising opposed grinding and .regulating wheels forming a work receiving throat therebetween, a work rest projecting within the throat for supporting work pieces therein and a work holding member for engaging a terminal portion of the work and-oscillatable from a work receiving position to a position to present a projecting portion of the work on the work rest in the throat between grinding and regulating wheels, means supporting the fixture for free floating movement to permit the work to automatically adjust itself to the grinding throat, and means for limiting said movement in one direction when the work is within the grinding throat.

to present a projecting portion of the work on the work rest in the throat between grind ing and regulating wheels, means supporting the fixture and work for free floating movement, means for limiting said movement in one direction when the workis within the grinding throat, and means for shifting the work axially of the fixture when in A grinding position.

' 4. A machine for the centerless produc- I tion of concentric work piece surfaces comprising opposed grinding and regulating wheels forming a work receiving throat therebetween, a work rest projecting within the threat for supporting work pieces therein and a Work holding member oscillatable from a work receiving position to a position to present a projecting portion of the work on the work rest in the throat between grinding and regulating Wheels, means supporting the fixture and work for free floating movement, means for limiting said movement in one direction when the work is within the grinding throat, means for shifting the work axially of the fixture when in'grinding position, and means for limit' ing said shifting movement. v 5. A centerless grinder' including a grinding wheel rotatable at a high grinding rate of speed and of appreciable width, an opposed regulating wheel having a narrow work engaging portion said wheel being movable at a-slow rate of speed to controlthe position and-rotation of the work piece, and a work rest sub-tending the throat between grinding-i and regulating wheels and having a projecting work engaging lug for engagement with the same zone on" the work as is engaged by the regulating wheel whereby the position of the work piece as a whole in the grinding throat is determined by the engagement of the regulating wheel and thereof, and means projectable into cngagement with the supported portion of the work when the work is in grinding position for urging the work axially into the grinding throat.

7. A centerless grinder including opposed grinding and regulating wheels forming a work receiving throat therebetween, a work rest within the throat, a hollow Work holding member exterior of the throat, a housing, a gimbal joint connecting the work holding member with the housing whereby the work holding member may be oscillated from a work receiving position to a position the bracket exterior of the grinding throat swingable from a position to receive unfinished pieces and have finished ones removed therefrom to a position to have a projecting portion of the work resting on the work rest blade, said,work receiving member having a portion for engagement with the terminal part of the work and to present a projecting portion-of the work oflering no interference to the normal floatpiece within the grinding throat on the work rest blade, and means projectable from the housing into the hollow work holding member for axially moving the work piece on the work rest blade into the grinding throat.

8. A centerless grinder includin opposed grinding and regulating wheels orming a work receiving throat therebetween, a work rest within the throat, a hollow work holding member exterior of the throat, a hous-' tion to present a projecting portion of the Work piece within the grinding throat on the work rest blade, means projectable from the housing into the hollow work holding member for axially moving the work piece on the work rest blade into the grinding throat and means limiting the axial movement of the work piece along the work rest blade.

* 9. A centerless grinder including opposed grinding and regulating wheels forming a work receiving throat therebetween, a work rest within the throat, a hollow work holding member exterior of the throat, a housing, a gimbal joint connecting the work holding member with the housing whereby the work holding member may be oscillated from a work receiving position to a position to present a projecting portion of the work piece within the grinding throat on the l1. In a centerless grinder the combination of a bed, a grinding wheel rotatably supported thereby and operable at a high grinding rate of speed, an opposed regulatlng wheel rotatable at a relatively slow work controlling rate of speed, the wheels having their opposed surfaces spaced from one another to provide a grinding throat, a work rest blade beneath the grinding throat for supporting avwork piece during the grinding operation, a block supporting the work rest blade, a work carrier, and means pivotally mounting the carrier on the block for manual movement from a position to receive a work piece to a position for inserting a portion of the work projecting from the carrier on the work rest blade within the throat and for manually reversely actuating the carrier to the work re ceiving position where the finished work is removed from the carrier and an unfinished one placed therein.

In testimony whereof I afiix my signature.

CLEMENT BOOTH.

work rest blade, means pro ectable from the housing into the hollow work. holding memher for axially moving-the work piece on the work rest blade into the grindin throat,

. said means comprising a pin, a sli e block axially shlftable through the housing and carried by/ the pin, an arcuately swingable lever pivoted exteriorly on the liousin and means connecting the lever to the sli e block for changing the arcuate movement of the lever to rectilinear movement of the block.

10. In a centerless grinder the combination of a bed, a pair of opposed grindin O and regulating wheels carried thereby and I forming a grinding throat therebetween, a work rest blade subtending the grinding throat and adapted to support a workpiece while being operated upon by the said 

